Heart and Muscle Damage Overview

Heart and Muscle Damage

• This presentation discusses heart and muscle damage, covering learning outcomes, diagnosis and management, screening, assay of biomarkers, acute myocardial infarction, and a summary of the key factors.

Learning Outcomes

• Understanding how serum enzymes, proteins, and metabolites are used as diagnostic tools.
• Identifying methods used to measure serum enzymes, proteins, and metabolites.
• Applying diagnostic principles to acute myocardial infarction and heart failure.

Recap

• Diagnosis: Assessing the presence of a condition.
• Management: Strategies for treating a disease.
• Progression of disease: How the condition develops.
• Response to treatment: How the condition responds to therapies.
• Recurrence of disease: The potential for the condition to return
• Screening: Identifying potential cases among asymptomatic individuals.
  • Population screening: Testing a whole population, like newborns.
  • Selected group screening: Testing specific groups, such as obese patients for type II diabetes.
  • Individual screening: Testing specific individuals, for example, those with familial hypercholesterolaemia.

Tissue Specific Biomarkers

• These markers are only produced in specific tissue types
• They sharply increase in response to damage.
• They are usually present at extremely low levels in healthy individuals.
• They are measured easily with universal reference values.
• A combination of different tests is sometimes used to obtain a precise profile when a single test is insufficient.

Assay of Serum Biomarkers

• Enzyme activity: Measures the rate of a chemical reaction, such as that produced by aspartate aminotransferase. This measures the speed at which the enzyme converts the substances aspartate + 2-oxoglutarate to glutamate + oxaloacetate, using NAD+ and NADH.
  • Rate is often measured using the change in absorbance.
  • Extinction coefficient for NADH = 6.22 mM-1 cm-1
• Amount of protein/enzyme: Assays using immunological methods, like ELISA.
  • Different types of ELISA include direct, indirect, sandwich, and competitive ELISAs.
• Metabolites: Detecting chemical conversions to coloured products using spectrophotometric measurements.
  • The Beer-Lambert law is used and needs to remain within the linear range.

Acute Myocardial Infarction (AMI)

• Cause: Imbalance between myocardial (heart muscle) oxygen supply and demand which leads to injury/death of muscle tissue.

  • Often a result of coronary thrombosis.
  • The thrombosis results from a fissure or rupture of the intimal lining of the atherosclerotic plaque. This blockage reduces blood supply to the affected area

• CHD (Coronary Heart Disease): Leading cause of death in many countries, with approximately 64,000 deaths each year in the UK. One death in the UK every eight minutes. CHD is one of the UK's leading causes of death and the most common cause of premature death.

• Diagnosis:

  • Subjects with acute chest pain may be suffering from AMI, unstable angina, or other conditions.
  • AMI patients will show ST segment elevation in the Electrocardiogram (ECG).
  • Non-ST segment elevated MI (NSTEMI) is identified through changes in T waves or ST depression/no change in ECG.
  • Only approximately 75% of AMI patients show diagnostic changes in the ECG.

• Causes other than AMI: Other conditions can result in elevated biomarkers, including myocarditis (an inflammation of the heart muscle), and pulmonary embolism (a blockage in the pulmonary arteries).

• Summary: Serum proteins' diagnostic value is increased when using a sensitive detection method like ELISA. Reduced oxygen supply to the heart, leading to tissue death, defines myocardial infarction. Biochemical tests are necessary for confirming the diagnosis, despite the usefulness of non-biochemical methods.

This quiz covers key aspects of heart and muscle damage, focusing on diagnosis, management, and the role of biomarkers. It discusses the principles of assessing conditions like acute myocardial infarction and heart failure, along with strategies for treatment and screening methods. Enhance your understanding of critical diagnostic tools and disease progression.